PCI: Simplify size1 assignment logic

[ Upstream commit a55bf64 ]

In pbus_size_io() and pbus_size_mem(), a complex ?: operation is performed
to set size1.  Decompose this so it's easier to read.

In the case of pbus_size_mem(), simply initializing size1 to zero ensures
the size1 checks work as expected.

Link: https://lore.kernel.org/r/20241216175632.4175-4-ilpo.jarvinen@linux.intel.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Xiaochun Lee <lixc17@lenovo.com>
Stable-dep-of: 67f9085 ("PCI: Allow relaxed bridge window tail sizing for optional resources")
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: ij-intel

drivers/pci/setup-bus.c

@@ -927,9 +927,14 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size,
 
 	size0 = calculate_iosize(size, min_size, size1, 0, 0,
 			resource_size(b_res), min_align);
-	size1 = (!realloc_head || (realloc_head && !add_size && !children_add_size)) ? size0 :
-		calculate_iosize(size, min_size, size1, add_size, children_add_size,
-			resource_size(b_res), min_align);
+
+	size1 = size0;
+	if (realloc_head && (add_size > 0 || children_add_size > 0)) {
+		size1 = calculate_iosize(size, min_size, size1, add_size,
+					 children_add_size, resource_size(b_res),
+					 min_align);
+	}
+
 	if (!size0 && !size1) {
 		if (bus->self && (b_res->start || b_res->end))
 			pci_info(bus->self, "disabling bridge window %pR to %pR (unused)\n",
@@ -1058,7 +1063,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
 			 struct list_head *realloc_head)
 {
 	struct pci_dev *dev;
-	resource_size_t min_align, win_align, align, size, size0, size1;
+	resource_size_t min_align, win_align, align, size, size0, size1 = 0;
 	resource_size_t aligns[24]; /* Alignments from 1MB to 8TB */
 	int order, max_order;
 	struct resource *b_res = find_bus_resource_of_type(bus,
@@ -1153,9 +1158,11 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
 			 b_res, &bus->busn_res);
 	}
 
-	size1 = (!realloc_head || (realloc_head && !add_size && !children_add_size)) ? size0 :
-		calculate_memsize(size, min_size, add_size, children_add_size,
-				resource_size(b_res), add_align);
+	if (realloc_head && (add_size > 0 || children_add_size > 0)) {
+		size1 = calculate_memsize(size, min_size, add_size, children_add_size,
+					  resource_size(b_res), add_align);
+	}
+
 	if (!size0 && !size1) {
 		if (bus->self && (b_res->start || b_res->end))
 			pci_info(bus->self, "disabling bridge window %pR to %pR (unused)\n",